Which experiment led to the measurement of the charge on an electron?
Mass spectrometric experiment
Oil-drop experiment
Scattering α - particles
Discharge-tube experiment
Correct answer is B
In 1909, Robert Millikan and Harvey Fletcher conducted the oil drop experiment to determine the charge of an electron.
15.50 g
7.10 g
3.55 g
1.80 g
Correct answer is C
2 * 35.5g of chlorine has a volume of 22.4 dm3 at s.t.p
∴ xg of chlorine will have a volume of 1.12 dm3
x = (1.12 * 35.5 * 2)/22.4 = 3.55g
2, 1, 2
4, 1, 2
4, 2, 1
1, 2, 1
Correct answer is C
No explanation has been provided for this answer.
The oxidation state of oxygen in tetraoxosulphate (VI) acid is
-4
-2
+4
-8
Correct answer is B
H2SO4
(O.N of hydrogen * 2 ) + O.N of sulphur + O.N of oxygen * 4 = 0
∴ 1 * 2 + 6 + 4x = 0
2 + 6 + 4x = 0
8 + 4x = 0
4x 0 - 8 = -8
4x = -8
x = -8/4 = -2
Calculate the number of moles of HCl present in 20cm3 of a 0.75M solution of the acid
0.015 mole
0.038 mole
3.800 moles
1.500 moles
Correct answer is A
Number of moles = (conc. in mol/dm3*volume in cm3)/1000
(0.75 * 20)/100 = 0.015 mole